Python Pandas CategoricalIndex - 類似於 dict 一樣使用輸入對應關係對映值


要使用類似於 dict 的輸入對應關係對映值,請在 Pandas 中使用 CategoricalIndex.map() 方法。首先匯入所需的庫 −

import pandas as pd

使用 "categories" 引數設定分類的類別。使用 "ordered" 引數將分類視為有序的 −

catIndex = pd.CategoricalIndex(["P", "Q", "R", "S","P", "Q", "R", "S"], ordered=True, categories=["P", "Q", "R", "S"])

顯示 CategoricalIndex −

print("CategoricalIndex...\n",catIndex)

對映類別 −

print("\nCategoricalIndex after mapping...\n",catIndex.map({'P': 5, 'Q': 10, 'R': 15, 'S': 20}))

示例

以下是程式碼 −

import pandas as pd

# Set the categories for the categorical using the "categories" parameter
# Treat the categorical as ordered using the "ordered" parameter
catIndex = pd.CategoricalIndex(["P", "Q", "R", "S","P", "Q", "R", "S"], ordered=True, categories=["P", "Q", "R", "S"])

# Display the CategoricalIndex
print("CategoricalIndex...\n",catIndex)

# Get the categories
print("\nDisplayingCategories from CategoricalIndex...\n",catIndex.categories)

# Map categories
print("\nCategoricalIndex after mapping...\n",catIndex.map({'P': 5, 'Q': 10, 'R': 15, 'S': 20}))

輸出

這將產生以下輸出 −

CategoricalIndex...
CategoricalIndex(['P', 'Q', 'R', 'S', 'P', 'Q', 'R', 'S'], categories=['P', 'Q', 'R', 'S'], ordered=True, dtype='category')

DisplayingCategories from CategoricalIndex...
Index(['P', 'Q', 'R', 'S'], dtype='object')

CategoricalIndex after mapping...
CategoricalIndex([5, 10, 15, 20, 5, 10, 15, 20], categories=[5, 10, 15, 20], ordered=True, dtype='category')

更新於: 18-Oct-2021

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